Stabfeldwebel Johann Lasi (born 1890, date of death unknown) was a World War I Austro-Hungarian flying ace, a Croat by ethnicity, credited with five aerial victories on 22 Aug 1916, while acting as an unauthorized rear gunner for Julius Arigi.

Johann Lasi was born in Kać, Bács-Bodrog, Hungary, Austria-Hungary (present day Serbia) in 1890.

On 22 August 1916, a formation of six Italian Farman two-seaters attacked the naval air station at Durazzo.

Julius Arigi of Flik 6 was poised in his Hansa-Brandenburg C.I to intercept the enemy formation, but could not find an observer.

By regulation, only an officer could man the rear gun, but Arigi could not find one that day, and asked 25-year-old Lasi to fly with him.